680 AETHUfl WILLEY. 



EXPLANATION OF PLATE 47, 



Illustrating Mr. Arthur Willey's paper, '' Spengelia, a New 

 Genus of Enteropneusta." 



Fig. 1. — Dorsal view of Spengelia porosa, after a sketch from the 

 living animal, showing the dermal pits behind the branchial grooves, p. Pro- 

 boscis, c. Collar, d. g. Median dorsal groove, br. g. Branchial or branchio- 

 genital groove, d.p. Dermal pits. 



Fig. 2. — Macroscopic section through the mid-branchial region of Spengelia, 

 showing the medial gonads and the oesophageal groove, m. g. Medial gonad. 

 d. I. m. Dorsal longitudinal musculature. hr.g. BrancLio-genital groove, 

 p. /. m. Ventro-lateral longitudinal musculature. /. g. Lateral gonads, ce. 

 (Esophageal groove, br. s. Branchial sac. 



Fig. 3. — Portion of branchial skeleton of Spengelia, to show synapticula. 

 From a preparation treated with caustic soda and mounted in glycerine. 

 Zeiss, 3 A, cam. luc. t. b. Skeleton of tongue-bar. s. b. Skeleton of primary 

 or septal bar. «y. Synapticula. 



